Antibiotic Cycling Reverts Extensive Drug Resistance in Burkholderia multivorans

Antibiotic collateral sensitivity, in which acquired resistance to one drug leads to decreased resistance to a different drug, occurs in Burkholderia multivorans . Here, we observed that treatment of extensively drug-resistant variants from a cystic fibrosis (CF) sputum sample with either meropenem or sulfamethoxazole-trimethoprim, depending on past resistance phenotypes, resulted in increased sensitivity to five different classes of antibiotics. We further identified mutations, including putative resistance-nodulation-division efflux pump regulators and uncharacterized pumps, that may be involved in this phenotype in B. multivorans .